HIGH TEMPERATURE FURNACE ON AN IMAGING PLATE SCANNER SYSTEM. A. Baumgarte, J. Schreuer, M. A. Estermann and W. Steurer, Laboratory of Crystallography, ETH Zentrum, CH-8092 Zurich, Switzerland

A compact furnace operating up to 1500K under helium atmosphere for an imaging plate scanner system (marresearch) was developed to record large amounts of reciprocal space at elevated temperatures [1]. The complex scattering phenomena connected with the phase transitions of decagonal quasicrystals and corresponding approximant phases in the Al-Co-Ni system will be presented.

The heating chamber consists of a watercooled cylindrical tube with radiation windows of Kapton foil, a rotatable feedthrough to connect the spindle axis with the goniometer and a heating element of two winded Kanthal wires above and below the sample, so that up to 2(=37[[ring]] no restriction for data recording results. The heating element, including radiation shields and an internal collimation system, can be rotated and translated along the phi-axis which allows for in situ observation of the crystal by the integrated CCD-camera of the scanner system.

For the high temperature heat measurement we developed a new kind of sample holder. The crystal is clamped between 4-6 polycrystalline aluminium oxide fibres of 10 microns in diameter.

The practicability of the furnace is demonstrated with fife different Al-Co-Ni crystals with decaprismatic morphology which undergo several phase transitions between ambient temperature and 1500K. Diffuse scattering and different types of satellite reflections were observed.

[1] J. Schreuer, A. Baumgarte, M. A. Estermann, W. Steurer and H. Reifler. Journal of Applied Crystallography (1996). in press.